We present a decade of dissolved and particulate silica concentrations within five biological “hot spots” in the Pacific Arctic Region (PAR) and the first measurements of both biogenic silica production rates (ρSi) and the kinetics of silicon utilization from a period of four years at the same sites. The “hot spots” were located within the Bering and Chukchi Seas and identified as part of the Distributed Biological Observatory (DBO). Across all hot spots, the highest concentrations of silicic acid (Si(OH)₄) and biogenic silica were found near the bottom of the euphotic zone and often correlated with increased ρSi. For the entire region, the average ρSi was 19 mmol m⁻² day⁻¹ and siliceous microplankton (i.e., diatoms) contributed an average of 62% to primary productivity and 82% to nitrate utilization. Irradiance and [Si(OH)₄] had separate and interactive effects on ρSi. Irradiance modulated both the magnitude of ρSi and the response of diatoms to changes in Si(OH)₄. Availability of Si(OH)₄ limited ρSi in all hot spots in at least one of the four years. Kinetic experiments conducted in all hot spots demonstrated that the half‐saturation constant (K_s) for ρSi was 4–8 times higher than ever reported in the literature. In the southeastern Chukchi Sea, an east to west gradient in [bSiO₂] and ρSi may have been driven by differences in the availability of NO₃⁻ rather than Si(OH)₄. Despite strong interannual variability, we suggest that phytoplankton phenology responds to short‐term climatic changes, which can have far‐reaching effects on Arctic regions influenced by the Pacific‐origin waters flowing through the PAR.

中文翻译：

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2006年至2016年太平洋北极地区夏季生物硅产量和硅含量的限制

我们介绍了太平洋北极地区（PAR）五个生物“热点”中溶解的二氧化硅和颗粒二氧化硅的浓度，以及四个时期以来首次测量了生物二氧化硅的生产率（ρSi）和硅利用动力学。年在同一地点。这些“热点”位于白令海和楚科奇海中，被确定为分布式生物观测台（DBO）的一部分。在所有热点，硅酸的最高浓度（SI（OH）₄）和生物来源二氧化硅附近发现了透光层的底部，并常常具有增加的相关ρ的Si。在整个区域，平均ρSi为19 mmol m ^-2 天^-1硅质浮游生物（即硅藻）平均贡献了初级生产力的62％和硝酸盐利用率的82％。辐照度和[Si（OH）₄ ]对ρSi具有独立的相互作用。辐照度调制的两个幅度ρ Si和硅藻到变化的Si（OH）的反应₄。可用性的Si（OH）₄限于ρ的Si中的所有热点的四年中的至少一个。在所有的热点进行动力学实验表明，半饱和常数（ķ_小号）为ρ的Si高出4-8倍，比在文献中曾报道。在楚科奇海东南部，[bSiO₂ ]和ρ的Si可能已被驱动而在NO的可用性差异₃ ^-而不是硅（OH）₄。尽管年际变化很大，但我们建议浮游植物物候对短期气候变化做出反应，这可能对受流经PAR的太平洋水域影响的北极地区产生深远影响。